Telephone transmission system.



J.. G. R. PALMER.

, TELEPHONE TRANSMISSION SYSTEM.

APPLICATION FILED DEG. 16, 1910.

Patented Nov. 26, 19.12.

'UN1TE FI IECE.

JOEL C. R. PALMER, OF BROOKLYN, NEW YORK, ASSIGNOR T0 WESTERN ELECTRIC COMPANY, OF NEW YORK, N. Y., A. CORPORATION OF ILLINOIS.

. TELEPHONE TRANSMISSION SYSTEM.

To all whom it may concern:

Be it known that I, JOEL O. R. PALMER, citizen of the United States, residing at Brooklyn, in the county of Kings and State of New York, have inventeda certain new and useful Improvement in Telephone Transmission Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to a telephon transmission system and more particularly to a transmission system for a compar tively long line with which isassociated a plurality of substations.

One of the objects of this invention is to provide a novel and improved arrangement of substation circuit apparatus whereby separate paths are provided at each substation for the outgoing and the incoming voice currents.

Another object of this invention is to provide means in connection with the path for incoming voice currents whereby when the path for outgoing voice currents is in circuit the path for the incoming voice currents will'have little or no shunting ellect upon the outgoing voice currents although permitting a sufficient flow of current to cause the operation of the talking operators receiver. I

In accordance with this invention there 18 provided at each substation on the line a transmitter circuit including a local battery,

transmitter and primary of an induction coil, a receiver circuit adapted to be bridged across the line, the secondary of an induction coil adapted to be placed in a I separate bridge across the line, an impedance element adapted to be cut into circuit with the receiver bridge and a switch ey arranged to simultaneously close the t ansmittr circuit, the secondary bridge and to cut the impedance element into circuit with the receiver bridge.

In the accompanying drawings-Figure 1 re resents a line circuit with a plurality of substations arranged in accordance with my invention connected therewith; Fig. 2 illustrates a modification of the substation arrangement shown in Fig. 1.

Referring particularly to Fig. 1, 5 and 6 designate line conductors uniting various waystations 7, 8, 9 and 10. At each of said stations is located a receiver 12 havin in series therewith a condenser 13, the receiver Specification of Letters Patent. Application filed. December 16, 1910. Serial No. 597,854.

a local battery message, key

Patented Nov. 26, 15-112.

and condenser being adapted to be placed in bridge of the line wires 5 and 6 by the operation of a'receiver switch hook 14 which closes switch hook contacts 15 and 16, said receiver bridge also including a normally closed contact 17 of a switch key 18. An impedance coil 19 normally in series with the receiver 12 is short-circuited by the closing of the key contact 17. A secondary 20 of an induction coil is bridged directly across the line in series with the. condenser 13 by the closure of a normally open contact 21 on said switch key 18. A second normally open contact 22 on said switch key 16 is adapted when closed to complete a circuit through a primary 23 of the induction coil,

24 and a transmitter 25, this circuit also'including the contact 16 on the receiver switch hook 14c.

Assuming now that an operator at one of the stations is listening and receiving a 18 remains in the position shown and the path for the incoming voice currents includes'the receiver 12 and the condenser 13 in bridge directly across the line wires 5 and 6. As the impedance coil 19 is short-circuited and the key contacts 21 and 22 are open this will be the only path. When the operator at any one of the stations desires to talk out over the line he actuates the switch key 18, opening the contact 17 and closing the contacts 21 and 22. The opening of the contact 17 removes the short-circuit of the impedance coil 19 putting it in series with the receiver which remains bridged across the line, the effect of this being that while-the path for the outgoing voice currents is not affected to any appreciable extent, any other operator desiring to break in may make himself heard by the talking party. The closing of the contact 21 places the secondary 20 of the induction coil in direct bridge of the line wires 5 and 6, while the closing of the contact 22 completes the battery circuit for the transmitter 25 thus enabling the operator to talk out on to the line.

The arrangement shown in Fig. 2 difi'ers slightly from that shown in Fig. 1 in that an extra normally open contact 27 is provided on the key 18 by means of which the impedance coil 19 is cut into and out of circuit with the receiver. In this arrangement there is only one contact on the receiver hook switch. As will be seen from this arrangeor the receiver bridge.

ment the receiver is in use for receiving ,a message when the secondary of the induction coil is out of circuit and the secondary is in use when the receiver is notefiectively in use; in other words, there are two distinct paths one for the incoming voice currents and one for the outgoing voice currents, each. being rendered practically ineil'ective to the class of currents which is caused to pass through the other.

1 across said line circuit, means for decreasing-or eliminating the flow of voice currents through said secondary Winding and simultaneously decreasing the impedance 0 receiver circuit, and an independent bridge across said line circuit including a receiver.

"6. A telephone transmission system, comprising a pluarlity of stations united common line circuit, each station having a local transmitter circuit including the pri- I claim: mary winding 0 an induction coil, a secondl. A telephone transmission system comary winding for said coilbridged across prising a plurality of stations united by a sa id line circuit, means for decreasing or common line circuit, each station having a eliminating the flow of voice currents transmitter, a local battery, a primary wind-- ing of an induction coil, said transmitter, local battery and primary winding being adapted for interconnection, a secondary winding of said induction coil bridged across said line circuit, an independent bridge across the line circuit including a receiver, and means for at will increasing the impedance of the receiver bridge.

2. A telephone transmission system comprising a plurality oi? stations united by a common line circuit, each station having a local transmitter circuit including the primary-winding of an induction coil, a secondary winding for said coil bridged across said line circuit,

a receiver in an independent bridge means for through said secondary winding and simultaneously decreasin the impedance of the receiver circuit, an a receiver in an independent bridge across said line circuit.

prising a plurality of stations united by a common line circuit, each station having a transmitter, a local battery, a primary winding of an induction coil, said transmitter, local battery and primary winding being adapted for interconnection, a secondary winding of said induction coil bridged the impedance of the receiver circuit an simultaneously closing the local transmitter circuit, means for decreasing the flow of voice currents through said secondary winding and simultaneously decreasing the im pedance of the receiver circuit, and an independent bridge across said line circuit including a receiver.

8. A telephone transmission system comprising a plurality of stations united by a common line circuit, each station having a including the priacross said line circuit, and at will increasing the impedance 3. A telephone transmission system comprising a plurality of stations united by a common line circuit, each station having a transmitter, a local battery, a primary Winding of an induction coil, said transmitter, local battery and primary wi ding being adapted for interconnection, a secondary winding of said induction coil bridged. across said line circuit, means for increasing the impedance of the receiver circuit and simultaneously closing the local transmitter circuit, and an independent bridge across said line circuit including a receiver.

4. A telephone transmission system comprising a plurality of stations united by a common line circuit, each station having a local transmitter circuit including the primary winding of an induction. coil, a secondary winding for said coil bridged across said line circuit, means for increasing the impedance of the receiver circuit and simultaneously closing the local transmitter circuit, and a receiver in an independent bridge across said line circuit.

5. A telephone transmission system comprising a plurality of stations united by a common line circuit, each station having a transmitter, a local battery, a primary Windlocal transmitter circuit mary winding of an induction coil, a secondary windin for said induction coil bridged across said ne circuit, means for increasin the impedance of the receiver circuit an simultaneously circuit, means for decreasing or eliminating the flow of voice currents through said secondary winding and simultaneously decreasing the impedance of the receiver'circui and a receiver in an across said line circuit.

prising a common local transmitter circuit including the primary winding of an induction coil, a secondary winding for said'coil adapted for bridge connection across said line circuit, means for increasingthe impedance of the receiver circuit and simultaneously closing transmitter circuit, and a receiver in an independent bridge across said line circuit. ing of an induction coil, said transmitter, 10. In a telephone system, saline and a and primary winding being k subscribers set including a receiver, an implurality of stations united by a local battery adapted for interconnect on, a secondary pedance device in series therewith, a shorts winding of said induction coil bridged circii'iting shunt circuit connected tothe terf the 7 A telephone transmission system coinacross said line circuit, means for increasing 9. A telephone transmission system comline circuit, each station having athe local closing the local transmitter independent bridge pedance i saio impedance, and means for osing said shunt circuit.

. a telephone system, a line, and a subscrili s set inciuding a receiver, an imcvice in series therewith, a shunt circuit around said impedance device, normally closed and short-circuiting said device, and a switch for. opening said short circuit.

in a telephone system, a line and a partys set ceivcr, an impedance coil in series with the receiv a shunt around the impedance coil, and tch controlling the shunt and efi'ectin operative connection of the teensn'iitter with the line, arranged automatically to close the shunt when the transmitter is disconnected from the line, and to disable the-transmitter when the shunt is closed.

1.25. in a telephone system, a telephone receiver circuit, a normally disabled impedance device in said receiver-circuit, a talking circuit including an induction coil secondand means for rendering said talking ci cuit effective and simultaneously rendering said impedance device effective.

is In a telephone system, line wires, a telephone receiver circuit in bridge of said comprising a transmitter, a re-- line Wire-s, means for increasing the impcdance of the receiver circuit, a talking circuit including an induction coil secondary in a normally open bridge of said line Wires, and switching means and connections for simultaneously closing the bridge of said induction coil secondary and increasing the impedance of the receiver circuit.

15. A telephone transmission system comprising a line circuit, a subscribers station having a local transmitter circuit including the primary Winding of an induction coil, a

secondary for said induction coil in a normally open bridge of said line circuit, a receiver in an independent bridge of said circuit, a normally disabled impedance device in said receiver circuit, and switching means and connections for simultaneously closing said transmitter circuit, completing the bridge of said secondary Winding and rendering said impedance device eifective.

In Witness whereof, I, hereunto subscribe my name this 15th day of Dec. A. D. 1919.

JOEL C. R. PALlliER.

Witnesses:

IRvINo MACDONALD, MORGAN WASHBURN, Jr.

djcpies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

